Being around until 4th Dan, you naturally will see teaching perspectives. I do believe that 3rd Dan should assist in teaching responsibilities, such that when they go out on their own, at 4th Dan, they have that experience. It is during the 3rd dan period that the assistant instructor starts thinking about how they will keep this, or change that, or get rid of this in favor of that, etc. Then at 4th Dan, they get to test their own theories out on their own students. When students open their own dojang, I as a general rule give them complete freedom to do and teach however they want. They can always come and ask, but they don't I generally keep my mouth shut and let them figure it out for themselves. Again, I am not into micromanaging or controlling my students. As 4th Dan, they can and should exercise their own freedom and judgment on how to do things. Similarly, when you start your own family, your parents leave you alone and you raise your kids as you see fit. Same thing. Ultimately, the martial arts, and life is about freedom, making choices, learning from those choices, and living with the consequences of those choices.